1. Field of the Invention
This invention relates generally to fall arresting ladder safety devices, and more particularly to fall arresting ladder safety devices that attach to a ladder side rail rather than a rigid carrier rail or carrier cable extending along the centerline of the ladder.
2. Description of the Related Art
As required by the Occupational Safety and Health Administration (OSHA) regulations (29 C.F.R. .sctn.1926.1053(a)(19)), all fixed ladders that have a length of climb equal to or exceeding 24 feet (7.3 meters) must be equipped with fall arresting ladder safety devices, or self-retracting lifelines, or a ladder cage. Additionally, where the length of climb exceeds 50 feet (15.2 meters), rest platforms or offset landings must be provided on the ladders.
Conventional fall arresting ladder safety systems, such as those sold under the trademarks Saf-T-Climb.RTM., a registered trademark of Siebe North Inc., and Lad-Saf.RTM., a registered trademark of D B Industries, Inc., include a carrier device which is attached to a rigid carrier rail or a carrier cable for movement therealong. The carrier rail or cable extends vertically along the length of the ladder and is disposed a distance outward from the ladder rungs along the centerline thereof. A lanyard, typically six feet (1.8 meters) in length is connected at one end to the carrier device with the other end connected to the body harness of the climber. As the climber ascends or descends the ladder, the carrier device is pulled along the carrier rail or cable with the climber. If the climber loses his or her footing, or for some other reason falls from the ladder, the carrier device lockably engages the rigid carrier rail or cable such that the climber will only free fall the distance of the length of the lanyard. Thus, the climber's free fall is arrested after only a short distance.
However, there are a number of disadvantages to the rail or cable type systems. For climbers who must utilize such devices, the main disadvantage is inconvenience. On the rail or cable type system, the carrier device is dragged up and down the carrier rail or cable behind the climber and often binds up, requiring the climber to stop his or her ascent or descent to unbind the carrier. Such binding of the carrier is an annoyance and inconvenience to the climbers.
Another disadvantage to such systems is that the climber must straddle the carrier rail or cable with one hand and one foot on each side of the carrier rail or cable as he or she climbs the ladder. This is also an annoyance to the climber who would much rather have an unobstructed ladder rung on which to place his or her hands and feet during climbing or working off of the ladder.
Yet another disadvantage of the rail or cable type systems is that each fixed ladder must be specially equipped with the special carrier rail or cable and one or more carrier devices. Equipping ladders with these special carrier rails or cables and carrier devices can be quite expensive, especially if the site or facility on which the system is installed is greater than 50 feet in height requiring a series of offset ladders and landings or rest platforms.
Thus, those concerned with these and other problems recognize the need for an improved fall arresting ladder safety device.